Method and apparatus for substrate transfer and radical confinement

ABSTRACT

Embodiments of the present invention provide an apparatus for transferring substrates and confining a processing environment in a chamber. One embodiment of the present invention provides a hoop assembly for using a processing chamber. The hoop assembly includes a confinement ring defining a confinement region therein, and three or more lifting fingers attached to the hoop. The three or more lifting fingers are configured to support a substrate outside the inner volume of the confinement ring.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/963,758, filed Apr. 26, 2018, which is a divisional of U.S.application Ser. No. 13/985,843, filed Feb. 29, 2012, now U.S. Pat. No.10,090,181, which claims the benefit of International Application No.PCT/US2012/027097, filed Feb. 29, 2012, which claims benefit of U.S.provisional patent application Ser. No. 62/448,012, filed Mar. 1, 2011,all of which are incorporated herein by reference in their entireties.

BACKGROUND Field

Embodiments of the present invention generally relate to a method andapparatus for fabricating devices on a semiconductor substrate. Moreparticularly, embodiments of the present invention provide an apparatusfor transferring substrates and confining a processing environment in achamber.

Description of the Related Art

During manufacturing of semiconductor devices, a substrate is usuallyprocessed in a processing chamber, where deposition, etching, andthermal processing may be performed to the substrate. Improving processuniformity and reducing particle contamination are two constant goalsfor semiconductor processing, especially as dimensions of semiconductordevices rapidly reduce.

A semiconductor processing chamber generally includes a chamber bodydefining an inner volume for processing a substrate. A substrate supportis usually disposed in the inner volume to support the substrate duringprocessing. One or more slit valve doors may be formed through thechamber body to allow passage of the substrate into and out of the innervolume. Gas supply paths and pumping channels are also formed throughthe chamber body to provide processing gas and pump the inner volume toa desired pressure. The slit valve opening, the gas supply paths, thepumping channels, and the substrate support usually cause the inner wallof the chamber body to be asymmetrical and/or irregular, thus causingnon-uniform conductance and/or electric field asymmetries. As a result,different areas on the substrate may be exposed to different processingconditions and uniformity of processing across the substrate decreases.Furthermore, the processing gas may travel to the slit valve area andcause contamination around the slit valve area.

Therefore, there is a need for methods and apparatus for improvingprocess uniformity and reducing contamination in a semiconductorprocessing chamber.

SUMMARY

Embodiments of the present invention generally provide apparatus andmethods for processing a substrate. More particularly, embodiments ofthe present invention provide an apparatus for transferring substratesand confining a processing environment in a chamber.

One embodiment of the present invention provides a hoop assembly for usein a processing chamber. The hoop assembly includes a confinement ringdefining a confinement region therein, and three or more lifting fingersextending below the confinement ring. Each of the three or more liftingfingers has a contact tip positioned radially inward from theconfinement ring to form a substrate support surface below and spacedapart from the confinement region defined by the confinement ring.

Another embodiment of the present invention provides a chamber forprocessing a substrate. The chamber includes a chamber body defining achamber volume therein, a substrate support pedestal assembly disposedin the chamber volume, and a hoop assembly moveable within the chambervolume. The chamber body has a sealable substrate transfer opening. Thehoop assembly includes a confinement ring movable between an elevatedposition and a lowered position. The confinement ring defines aconfinement region above the substrate support pedestal assembly in thelowered position.

Yet another embodiment of the present invention provides a method forprocessing a substrate. The method includes transferring a substratethrough an opening of a processing chamber to three or more liftingfingers of a hoop assembly disposed in the processing chamber. The hoopassembly comprises a confinement ring defining a cylindrical confinementregion therein. The method further includes lowering the hoop assemblyto transfer the substrate from the lifting fingers to a substratesupport pedestal assembly disposed in the processing chamber, andpositioning the hoop assembly in a processing position. The confinementregion is at least immediately above the substrate disposed on thesubstrate support pedestal assembly with the confinement ring shieldingthe opening. The method further includes processing the substrate bysupplying a processing gas to the confinement region with the hoopassembly in the processing position.

In the method described above, a height of the confinement ring spansfrom the substrate to a lower surface of a showerhead positioned abovethe substrate support pedestal assembly when the hoop assembly is in theprocessing position. The method above may further include elevating theconfinement ring into a cavity formed in a ceiling of the processingchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a schematic sectional view of a load lock chamber having ahoop assembly according to one embodiment of the present invention.

FIG. 2 is a schematic sectional view of the load lock chamber of FIG. 1with the hoop assembly in a loading/unloading position.

FIG. 3 is a schematic top view of a load lock chamber having a hoopassembly according to one embodiment of the present invention.

FIG. 4 is an exploded view of the hoop assembly according to oneembodiment of the present invention.

FIG. 4A is a partial sectional view of the hoop assembly.

FIG. 4B is a partial view of a sector of the hoop assembly viewingoutward from the center of the hoop assembly.

FIG. 5 is a sectional view of a hoop body according to one embodiment ofthe present invention.

FIG. 6 is a perspective view of a lifting finger according to oneembodiment of the present invention.

FIG. 7 is a partial sectional side view of the hoop assembly showing alift actuator having a bellows according to one embodiment of thepresent invention.

FIGS. 8A and 8B schematically illustrate the bellows in extended andcompressed position.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

Embodiments of the present invention provide apparatus and methods forfabricating devices on a semiconductor substrate. More particularly,embodiments of the present invention relate to a substrate transferapparatus having a structure for bounding a movable confinement regionwithin a process volume of a processing chamber. The structure forbounding a movable confinement region may also be utilized withoutfeatures for transferring a substrate within the processing chamber.

Embodiments of the present invention provide a hoop assembly for use ina chamber, such as a processing chamber or a load lock chamber. The hoopassembly includes three or more lifting fingers and a confinement ring.A lift actuator may be utilized to move the hoop assembly up and down.The hoop assembly can be used to pick up a substrate from a substratesupport pedestal assembly using the lifting fingers, and to allow robotblades to transfer substrates in and out of the chamber by transferringthe substrates to and from the lifting fingers. The confinement ring hasa cylindrical inner wall that is substantially symmetric and defines andradially bounds a confinement region within a processing volume of thechamber. The confinement ring can be moved to a position circumscribingthe substrate and substrate support pedestal assembly to create asymmetric confinement region around and immediately above the substrateby surrounding the substrate with its inner wall, thus eliminatingprocessing non-uniformity cased by asymmetric or irregular shapes of thechamber walls, for example the effects of the slit tunnel area thatconnects the inner chamber volume to a slit valve door. Additionally,the confinement ring also reduces exposure of the slit tunnel area toprocess chemistry, thus keeping the slit tunnel area clean. Theconfinement ring may be formed from quartz material to reducerecombination of radicals around the substrate, theoretically increasingthe radical flux to the substrate and subsequent process performance.

FIG. 1 is a schematic sectional view of a dual load lock chamber 100having a hoop assembly 144 according to one embodiment of the presentinvention. Although the hoop assembly 144 is described in the context ofa load lock chamber having a processing volume, is it understood thatthe hoop assembly 144 may be utilized in any suitably adapted load lockand/or processing chamber, including those having a single processingvolume, where it is desirable to have a symmetrical confinement region.

The dual load lock chamber 100 includes an upper chamber volume 120 fortransferring and processing a substrate 104, and a lower chamber volume110 for transferring a substrate 104. The upper chamber volume 120 andthe lower chamber volume 110 are vertically stacked and are isolatedfrom one another. Each of the lower and upper load lock volumes 110, 120may be selectively connected to two adjacent external environments(i.e., a factory interface and transfer chamber, both not shown) throughtwo openings for substrate transferring.

The dual load lock chamber 100 includes a chamber body 103. In oneembodiment, the chamber body 103 includes an upper chamber body 121 anda lower chamber body 111 coupled together to define the upper and lowerchamber volumes 120, 110.

The dual load lock chamber 100 may include a showerhead 129 disposedover the upper chamber volume 120, a substrate support pedestal assembly132 disposed within the upper chamber volume 120, and a hoop assembly144 to define a confinement region in the upper chamber volume 120 aswell as to load and unload substrates. The dual load lock chamber 100may include supporting pins 113 for supporting a substrate 104 in thelower chamber volume 110.

The upper chamber volume 120 is defined by sidewalls 124 of the upperchamber body 121, a lid ring 127 disposed over the sidewalls 124, abottom wall 123 of the upper chamber body 121, and an upper wall 118 ofthe lower chamber body 111. The lid ring 127 has an inner lip 127 aholding the showerhead 129 and a source adapter plate 128. The lid ring127 forms a portion of the ceiling of the upper chamber volume 120. Thesource adapter plate 128 has a central opening 128 a that matches with acentral opening 129 e of the showerhead 129. A remote plasma source 130is in fluid communication with the upper chamber volume 120 through aquartz insert 131 and the showerhead 129.

The remote plasma source 130 is generally connected to one or more gaspanels. In one embodiment, the remote plasma source 130 is connected toa first gas panel 101 configured for providing processing gases for anabatement process to remove residual material after etching and a secondgas panel 102 configured for providing processing gases for an ashingprocess to remove photoresist.

It is also contemplated that one or more plasma generators may beoptionally utilized to sustain a plasma within the upper chamber volume120 in lieu of, or in addition to the remote plasma source 130. Theplasma generator may be RF driven coils positioned outside of or withinthe upper chamber volume 120, and/or an RF driven electrode, at leastone disposed in the substrate support pedestal assembly 132, above theshowerhead 129, or the showerhead 129 itself.

The substrate support pedestal assembly 132 is disposed in the upperchamber volume 120 for supporting and heating the substrate 104 usinginternal heaters (not shown). A focus ring 151 may be disposed on anouter edge of the substrate support pedestal assembly 132. The focusring 151 functions to retain the substrate 104 and to modify aprocessing rate around an edge area of the substrate 104 duringprocessing.

The substrate support pedestal assembly 132 is mounted on an insulator143 disposed on the upper wall 118 of the lower chamber body 111. Theinsulator 143 prevents heat transfer between the substrate supportpedestal assembly 132 and the chamber body 103. In one embodiment, theinsulator 143 aligns with a central axis 132 a of the substrate supportpedestal assembly 132 to ensure that the substrate support pedestalassembly 132 remains centered during thermal expansion.

A cantilever tube 136 is attached to a backside 134 b near the center ofthe substrate support pedestal assembly 132. The cantilever tube 136extends radially outwards to connect with a vertical tube 137. The tubes136, 137 do not contact the upper chamber body 121 or the lower chamberbody 111 to further avoid heat exchange between the substrate supportpedestal assembly 132 and the chamber bodies 111, 121. The cantilevertube 136 and the vertical tube 137 provide a passage for power supplies,sensors and other wiring to be used by the substrate support pedestalassembly 132. In one embodiment, a heater power source 138, a sensorsignal receiver 139 and a chucking control unit 140 are wired to thesubstrate support pedestal assembly 132 through the passage in thecantilever tube 136 and the vertical tube 137.

A cooling adaptor 141 is coupled to the vertical tube 137 from outsideof the lower chamber body 111. A source for cooling fluid 142 isconnected to cooling channels 141 a disposed in the cooling adaptor 141.The cooling adaptor 141 controls the rate and direction of heat exchangebetween the vertical tube 137, the cantilever tube 136, and thesubstrate support pedestal assembly 132. In one embodiment, thermalbreaks, such as bi-metal connectors, may be used for connecting verticaltube 137, the cantilever tube 136, and the substrate support pedestalassembly 132 to thermally isolate the substrate support pedestalassembly 132 from the chamber body 103, thereby allowing more precisecontrol and rapid response of the temperature of the substrate heated bythe pedestal assembly 132.

A more detailed description of the upper and lower chamber bodies can befound in U.S. Provisional Patent Application Ser. No. 61/448,027, filedMar. 1, 2011, entitled “Abatement and Strip Process Chamber in a DualLoad Lock Configuration” (Docket No. 15751L).

A more detailed description of the substrate support pedestal assembly132 can be found in U.S. Provisional Patent Application Ser. No.61/448,018, filed Mar. 1, 2011, entitled “Thin Heated Substrate Support”(Docket No. 15750L).

The hoop assembly 144 is disposed in the upper chamber volume 120according one embodiment of the present invention. As previously stated,the hoop assembly 144 may be used in other processing chambers and/orload lock chambers. The hoop assembly 144 has two functions. First, thehoop assembly 144 is vertically positionable to enable transfer ofsubstrates between the substrate support pedestal assembly 132 andsubstrate transfer devices (e.g., robot end effectors) entering theupper chamber volume 120. Second, the hoop assembly 144 defines asymmetrical confinement region 144 a around the substrate 104 and regionimmediately above the substrate support pedestal assembly 132 duringprocessing, thus, providing a symmetrical processing environment in theupper chamber volume 120 which enhances processing results. The hoopassembly 144 may also be utilized solely for establishing a symmetricalconfinement region within a processing volume.

The hoop assembly 144 includes a ring-shaped hoop body 146 disposedwithin the upper chamber volume 120. The ring-shaped hoop body 146 hasan inner diameter which is greater than a diameter of the substratesupport pedestal assembly 132. The hoop body 146 is coupled to a shaft160 that extends through the chamber body 103 to a lift actuator 169.The lift actuator 169, such as a linear actuator or motor, is operableto control the vertical elevation of the hoop body 146 within the upperchamber volume 120. In one embodiment, bellows 161 are provided toprevent leakage between the shaft 160 and the chamber body 103.

The hoop assembly 144 also includes three or more lifting fingers 147attached to the hoop body 146. The lifting fingers 147 are used totransfer substrates between the substrate support pedestal assembly 132and substrate transfer devices, such as robots, extending into the upperchamber volume 120 when the hoop assembly 144 is in an upper transferposition, as shown in FIG. 1. The lifting fingers 147 extend verticallydownwards and turn radially inwards from the hoop body 146, terminatingin a tip 147 a. The tips 147 a of the lifting fingers 147 form asubstrate support surface to support the substrate 104 at several pointsnear an edge region of the substrate 104. A spacing 179 is definedbetween a lower surface of the hoop body 146 and tips 147 a which issufficient to allow a robot end effector to lift a substrate 104 fromthe tips 147 a of the lifting fingers 147 without hitting the lowersurface of the hoop body 146.

The hoop assembly 144 also includes a confinement ring 145 supported bythe hoop body 146. The confinement ring 145 extends vertically upwardsfrom the hoop body 146. In one embodiment, the confinement ring 145 is acylindrical ring having a substantially cylindrical inner wall 145 a.The height 145 b of the inner wall 145 a is much greater than thethickness of the substrate 104 so that the inner wall 145 a can confinea portion of the upper processing volume as a symmetrical confinementregion 144 a around and above the substrate 104. In one embodiment, theheight 145 b of the inner wall 145 a of the confinement ring 145 is muchgreater than the thickness of the substrate support pedestal assembly132 to allow the confinement ring 145 to overlap the substrate supportpedestal assembly 132 while still extending sufficiently above thesubstrate 104 disposed on the substrate support pedestal assembly 132.The inner wall 145 a of the confinement ring 145 has a diameter greaterthan the outer diameter of the substrate support pedestal assembly 132.The inner wall 145 a of the confinement ring 145 may also have adiameter greater than the outer diameter of the showerhead 129. In oneembodiment, the confinement ring 145 has a height 145 b sufficient tosimultaneously overlap both the substrate support pedestal assembly 132and showerhead 129 during processing.

During processing, the lift actuator 169 may position the hoop body 146in a lowered, processing position, as shown in FIG. 2, so that theconfinement ring 145 bounds and thereby creates a cylindricalconfinement region 144 a within the upper chamber volume 120 around thesubstrate 104 disposed on the substrate support pedestal assembly 132.In the embodiment depicted in FIG. 2, the cylindrical confinement region144 a within the upper chamber volume 120 has a completely symmetricalcylindrical boundary as the inner wall 145 a shields the cylindricalconfinement region 144 a from asymmetries which may be present in thechamber body 103, such as slit valve tunnels and the like. Thesymmetrical processing environment provided by the cylindricalconfinement region 144 a enhances process uniformity by reducingconductance and/or electrical asymmetries which have a negative effecton substrate process uniformity.

The lifting fingers 147 of the hoop assembly 144 are aligned with cutouts 155 formed in the substrate support pedestal assembly 132. As thehoop assembly 144 is lowered, the tips 147 a of the lifting fingers 147pass below the upper surface 133 a of the substrate support pedestalassembly 132 and into the cut outs 155 thereby transferring thesubstrate 104 from the tips 147 a of the lifting fingers 147 to theupper surface 133 a of the substrate support pedestal assembly 132.Conversely, as the hoop body 146 is raised, the lifting fingers 147 moveupward through the cut outs 155 to come in contact with and lift thesubstrate 104 from the upper surface 133 a of the substrate supportpedestal assembly 132.

Returning back to FIG. 1, a cavity 127 b is formed in the lid ring 127which accepts the upper portion of the confinement ring 145 when thehoop assembly 144 is in the elevated position. In one embodiment, thecavity 127 b is an annular slot. The cavity 127 b allows the liftingfingers 147 to be aligned with the slit valve tunnel (not shown) therebyenabling substrate transfer with the robot end effector (also not shown)without increasing the volume of the upper chamber volume 120 toaccommodate the motion of the confinement ring 145 which woulddisadvantageously result in slower pumping times, increase gas usage,larger pumps, higher energy consumption and higher chamber fabricationcosts.

FIG. 3 schematically illustrates a top view of the hoop assembly 144positioned within the upper chamber volume 120 of the upper chamber body121 with the showerhead 129 removed. Two substrate transfer openings 325are formed through the sidewalls 124 to allow substrate transferring andpassage of external robots. A slit valve door (not shown) may beattached outside of each opening 325 to selectively seal the upperchamber volume 120 from the adjacent environments external to the upperchamber volume 120.

The hoop body 146 and the confinement ring 145 have an inner diameter145 d large enough to surround the substrate 104 and substrate supportpedestal assembly 132, thereby defining and bounding the symmetricalconfinement region 144 a directly above the substrate 104. The liftingfingers 147 extend radially inward from the hoop body 146 and theconfinement ring 145 to a diameter less than that of the substrate 104and substrate support pedestal assembly 132, thereby allowing thefingers 147 to support the substrate 104 when lifted above the substratesupport pedestal assembly 132.

In the embodiment shown in FIG. 3, three lifting fingers 147 are used todefine a substrate supporting surface. The three lifting fingers 147 arearranged so that the lifting fingers 147 do not interfere with the robotend effectors extending into the upper chamber volume 120 through theopenings 325. In one embodiment, the lifting fingers 147 form a Y shapewith single lifting finger 147 on the side of the hoop body 146connected to the shaft 160 and the remaining pair of lifting fingers 147located on the opposite side of the hoop body 146 and spaced equidistantfrom the single lifting finger 147.

As shown in FIG. 3, the upper chamber body 121 has an irregular (e.g.,not cylindrical) inner wall 321 with openings 325 for slit valve doorspositioned on opposite sides and extra cut outs 360, 361, 362 for theshaft 160, the vertical tube 137 connected to the substrate supportpedestal assembly 132, and vacuum ports 390. The confinement ring 145 ispositioned around the substrate support pedestal assembly 132 to shieldthe processing region (e.g., containment region 144 a) above thesubstrate 104 from the irregular shape of the inner wall 321 of theupper chamber body 121 (such as the substrate transfer openings 325) andprovide a substantially symmetrical vertical boundary radially aroundthe substrate support pedestal assembly 132 and region of the processingvolume directly thereabove. In one embodiment, the confinement ring 145and the substrate support pedestal assembly 132 are substantiallyconcentric.

FIG. 4 is an exploded view of the hoop assembly 144 according to oneembodiment of the present invention. An inner lip 483 of the hoop body146 extends radially inward and provides a substantially planar surfacefor supporting the confinement ring 145. The lifting fingers 147 may beattached to a lower surface 489 of the hoop body 146 using suitablefasteners, adhesives or other fastening method. In one embodiment,screws 476 may be used to attach the lifting fingers 147 to the hoopbody 146. The bellows 161 attached to an upper end of the shaft 160 maybe attached to a handle portion 485 of the hoop body 146. In oneembodiment, the bellows 161 may be attached to the hoop body 146 by oneor more screws 477. One or more shields 463, 464 may be disposed aroundthe bellows 161 to reduce particle contamination resulting from themotion of the bellows 161.

In one embodiment, the confinement ring 145 is a cylindrical sleeve ringwhose inner surface 471 is a cylindrical wall. An upper end 474 and alower end 472 of the confinement ring 145 may be substantially parallelto one another. The confinement ring 145 may include one or more throughholes 402 to allow viewing of the confinement region through theconfinement ring 145. In one embodiment, the confinement ring 145 may beformed from quartz. The quartz confinement ring 145 together with thequartz showerhead 129 creates a quartz lining for the plasma duringprocessing, therefore, reducing species recombination and particlecontamination.

A substantially vertical ridge 470 is formed on an outer surface 473 ofthe confinement ring 145. The vertical ridge 470 may not extendcompletely to the bottom the lower end 472 of the confinement ring 145to ensure the correct orientation of the confinement ring 145, asfurther discussed below.

In one embodiment, the hoop body 146 includes a frame portion 486 havinga cylindrical inner wall 487 and the handle portion 485 extendingradially outward from the frame portion 486 on one side. A substantiallyvertical notch 480 may be formed in the cylindrical inner wall 487 ofthe frame portion 486. The notch 480 may not extend completely to theinner lip 483 of the hoop body 146. The notch 480 mates with thevertical ridge 470 of the confinement ring 145, thereby locating theconfinement ring 145 to the hoop body 146 when assembled, as illustratedin FIG. 4A. Since the vertical ridge 470 extends from the upper end 474,the confinement ring 145 will only lay flat on the hoop body 146 if theridge 470 is engaged with the notch 480 with the lower end 472 of the ofthe confinement ring 145 oriented towards the hoop body 146, therebypreventing installation of the confinement ring 145 in an up-side-downorientation.

Referring to the partial view of the hoop assembly depicted in FIG. 4B,one or more raised locating features 499 extend upwards from the innerlip 483 of the hoop body 146. Each of the one or more raised locatingfeatures 499 mate with an associated slot 498 formed in the lower end472 of the of the confinement ring 145. The mating locating features 499and slots 498 ensure a predefined angular orientation of the confinementring 145 relative to the hoop body 146 that aligns the through holes 402to allow viewing of the confinement region through the confinement ring145 by a metrology sensor (not shown). In one embodiment, the hoop body146 has three locating features 499 spaced on the inner lip 483 of thehoop body 146 while the confinement ring 145 has three similarly spaceslots 498. The three or more raised locating features 499 create a planefor the confinement ring 145 to rest on so that the confinement ring 145does not tip or tilt.

To assemble, the ridge 470 of the confinement ring 145 and the notch 480of the hoop body 146 are first aligned, and the confinement ring 145 isslip-fit inside the cylindrical inner wall 487 so that the lower end 472of the confinement ring 145 rests on the inner lip 483 of the hoop body146. The ridge 470 of the confinement ring 145 is locked in the notch480 preventing relative motions between the confinement ring 145 and thehoop body 146. In one embodiment, the confinement ring 145 is removablydisposed on the hoop body 146 to allow easy replacement.

Through holes 481, 482 may be formed through the hoop body 146 formounting the lifting fingers 147 and the bellows 161 respectively. Inone embodiment, both the lifting fingers 147 and the bellows 161 areattached to the hoop body 146 from a lower surface 489 of the hoop body146.

FIG. 5 is a sectional view of the hoop body 146 along section 5--5 linesshown in FIG. 4. The hoop body 146 may be formed from a metal. In oneembodiment, the hoop body 146 is formed from aluminum. The lower surface489 of the hoop body 146 may be substantially flat. An upper surface 588of the hoop body 146 may be slanted to reduce the thickness and toreduce bulk of hoop body 146 from the handle portion 485 to the frameportion 486.

FIG. 6 is a perspective view of the lifting finger 147 according to oneembodiment of the present invention. Each lifting finger 147 may have anL shape with a vertical portion 677 connected to a horizontal portion678. A hole 676 may be formed on the vertical portion 677 and a threadedinsert 675 may be disposed in the hole 676. The threaded insert 675mates with the screw 476 for attaching the lifting finger 147 to thehoop body 146. The contact tip 147 a is positioned on an upper surface679 of the horizontal portion 678. When attached to the hoop body 146,the vertical portion 677 of the lifting finger 147 creates the spacing179 between the lower surface 489 of the hoop body 146 and the contacttips 147 a. The spacing 179 allows passage of substrates.

The vertical portion 677 and horizontal portion 678 of the liftingfinger 147 may be formed from a metal. In one embodiment, the verticalportion 677 and horizontal portion 678 are formed from aluminum. Thethreaded insert 675 may be formed from a wear and galling resistivematerial, such as NITRONIC® stainless steel. The contact tip 147 a maybe formed from a ceramic material to reduce particle generation fromcontacting the substrate. In one embodiment, the contact tip 147 a maybe formed from silicon nitride. The contact tip 147 a may include a ballor other raised feature 602 to reduce the area of surface contact withthe substrate.

FIG. 7 is a partial sectional side view of the hoop assembly 144 showingthe bellows 161 according to one embodiment of the present invention.Two shields 463, 464 are disposed around convolutions 761 of the bellows161 to prevent particles from entering and becoming entrapped in theconvolutions 761. In one embodiment, the bellows 161 is formed from acorrosion resistant material, for example HAYNES® 242 alloy.

In one embodiment, the convolutions 761 of the bellows 161 are designedto keep particles away from high stress locations to extend the lifetime of the bellows 161.

FIGS. 8A and 8B schematically illustrate a portion of the convolutions761 of the bellows 161 in extended and compressed positions,respectively. A concaved curve 862 is formed near an internal weldedlocation 863 of high stress. As shown in FIG. 8A, while the convolutions761 are at an extended position, external particles may enter theconvolutions 761 along path 861. As the convolutions 761 compress (asshown in FIG. 8B), the concaved curve 862 remains concaved and theparticles eventually gather at the bottom of the concaved curve 862where there is more clearance and lower stress. Thus, the bellows 161prevents particles from moving towards the internal welded location 863avoiding further stress at the internal welded location 863.

The hoop assembly 144 according to embodiments of the present inventionhas several advantages. First, the hoop assembly saves space andsimplifies the rest of the chamber design. Second, the hoop assemblyallows the chamber body geometry to be decoupled from the substrateconfinement region geometry, providing a symmetrical or otherpredetermined substrate confinement region even if the chamber body hasan irregular shape to accommodate other components in the chamber.Third, the hoop assembly allows the substrate processing area to besurrounded by material different than that of the chamber body. Forexample quartz, instead of aluminum, may be used to confine theprocessing environment to reduce radical recombination of the plasmawithin the processing area.

Furthermore, the geometry of the confinement ring 145 and the focus ring151 around the substrate support pedestal assembly 132 may be sized tocontrol the gas conductance therebetween. The conductance betweenconfinement ring 145 and the focus ring 151 may be selected to be highrelative to a conductance between the top of the confinement ring 145and the lid ring 127, thereby causing the majority of gas to flowdownward inside the confinement ring 145 through the confinement regionwhere the substrate 104 is located.

Even though a cylindrical hoop is described in the exemplaryembodiments, the hoop can be designed to have other shapes to meetdesign requirements. For example, a rectangular hoop may be used inchambers for transfer or processing of rectangular substrates whereinthe rectangular hoop still provides a symmetrical confinement region.Even though embodiments of the present invention are described above inapplication of load lock chambers, embodiments of the present inventioncan be applied to any process chamber.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

What is claimed is:
 1. A hoop assembly for use in a processing chamber,comprising: a confinement ring defining a confinement region therein; ahoop body mating with the confinement ring, the hoop body slanted toreduce a thickness across a diameter of the hoop body; and three or morelifting fingers attached to the hoop body and extending downwards,wherein each of the three or more lifting fingers has a contact tippositioned radially inward from the hoop body to form a substratesupport surface below and spaced apart from the confinement region. 2.The hoop assembly of claim 1 further comprising: a hoop body having alip supporting the confinement ring.
 3. The hoop assembly of claim 2,wherein each of the three or more lifting finger is attached to a lowersurface of the hoop body.
 4. The hoop assembly of claim 2, wherein eachlifting finger comprises: a vertical portion attached to the lowersurface of the hoop body; and a horizontal portion connected to thevertical portion and extending radially inward, wherein the contact tipis positioned on the horizontal portion.
 5. The hoop assembly of claim2, wherein the hoop body comprises: a frame portion defining a centralopening; and a handle portion connected to the frame portion at one sideoutside the central opening.
 6. The hoop assembly of claim 5, furthercomprising: a shaft attached to the handle portion of the hoop body. 7.The hoop assembly of claim 2, wherein the confinement ring has a ridgemating with a notch formed in the hoop body.
 8. The hoop assembly ofclaim 2, wherein the confinement ring is formed from quartz, and thehoop body formed from aluminum.
 9. The hoop assembly of claim 1, whereinthe confinement ring is a sleeve ring with a vertically extended sidewall, and one or more through holes are formed between an inner surfaceand an outer surface of the vertically extended side wall.
 10. A chamberfor processing a substrate, comprising: a chamber body defining achamber volume therein, the chamber body having a sealable substratetransfer opening; a substrate support pedestal assembly disposed in thechamber volume; a hoop assembly moveable within the chamber volume,wherein the hoop assembly comprises: a confinement ring defining aconfinement region therein; a hoop body mating with the confinementring, the hoop body slanted to reduce a thickness across a diameter ofthe hoop body; and three or more lifting fingers attached to the hoopbody and extending downwards, wherein each of the three or more liftingfingers has a contact tip positioned radially inward from the hoop bodyto form a substrate support surface below and spaced apart from theconfinement region, wherein the confinement ring of the hoop assembly ismovable between an elevated position and a lowered position, and theconfined region is above the substrate support pedestal assembly whenthe hoop assembly is in the lowered position.
 11. The chamber of claim10, wherein the elevated position of the confinement ring is above thesealable substrate transfer opening and the lowered position of theconfinement ring is in front of the sealable substrate transfer opening.12. The chamber of claim 10, further comprising: a showerhead disposedabove the substrate support pedestal assembly, wherein the height of theconfinement ring spans from a lower surface of the showerhead and anupper surface of the substrate support pedestal assembly.
 13. Thechamber of claim 10, further comprising: a lid having a cavity receivingthe confinement ring when the confinement ring is in the elevatedposition.
 14. The chamber of claim 10, wherein the confinement ring is asleeve ring with a vertically extended side wall, and one or morethrough holes are formed between an inner surface and an outer surfaceof the vertically extended side wall.
 15. The chamber of claim 10,wherein the confinement ring has a height that at least spans from thesubstrate support pedestal assembly to an elevation above the sealablesubstrate transfer opening.
 16. The chamber of claim 10, wherein theconfinement ring is formed from quartz.
 17. The chamber of claim 10,wherein the hoop body further comprises: a lip supporting theconfinement ring, wherein each of the three or more lifting finger isattached to a lower surface of the hoop body.
 18. The chamber of claim10, wherein the hoop body further comprises: a lip supporting theconfinement ring, and each lifting finger comprises: a vertical portionattached to the lower surface of the hoop body; and a horizontal portionconnected to the vertical portion and extending radially inward, whereinthe contact tip is positioned on the horizontal portion.
 19. A methodfor processing a substrate, comprising: transferring a substrate throughan opening of a processing chamber to three or more lifting fingers of ahoop assembly disposed in the processing chamber, wherein the hoopassembly comprises: a confinement ring defining a confinement regiontherein; a hoop body mating with the confinement ring, the hoop bodyslanted to reduce a thickness across a diameter of the hoop body; andthree or more lifting fingers attached to the hoop body and extendingdownwards, wherein each of the three or more lifting fingers has acontact tip positioned radially inward from the hoop body to form asubstrate support surface below and spaced apart from the confinementregion; lowering the hoop assembly to transfer the substrate from thelifting fingers to a substrate support pedestal assembly disposed in theprocessing chamber; positioning the hoop assembly in a processingposition wherein the confinement region is at least immediately abovethe substrate disposed on the substrate support pedestal assembly withthe confinement ring shielding the opening; and processing the substrateby supplying a processing gas to the confinement region with the hoopassembly in the processing position.
 20. The method of claim 19, whereina height of the confinement ring spans from the substrate to a lowersurface of a showerhead positioned above the substrate support pedestalassembly when the hoop assembly is in the processing position.